The recent development of portable electronic and electric instruments based on the progress to a ubiquitous society, size enlargement of display instruments and the like have resulted in a tendency to use films made of organic polymers as a material for element substrates including transparent conductive substrates, or for sealant members, instead of glass substrates, and therefore weight reduction and thickness reduction (slimming) of the instruments are desired. In this case, the films made of organic polymers are required to have high gas barrier performance against steam, oxygen and the like in order to maintain the reliability of electronic and electric parts including display elements and the like, and optical parts, and when used for the display parts of display elements, the films are further required to have high transparency in order to maintain visibility. Thus, various techniques such as laminating a transparent inorganic film on a film comprising an organic polymer, or laminating an organic layer and an inorganic layer, have been investigated (See, for example, Patent Document 1 and Patent Document 2).
When a film made of an organic polymer and having an inorganic film or the like laminated thereon is used as a sealant member for bonding with an adhesive resin in electronic and electric parts including display elements and the like, it is desirable that the sealant film and the adhesive resin are bonded uniformly and firmly, in order to prevent delamination of the sealant film and the like that is caused by environmental changes during product manufacturing processes after bonding of the sealant film or use of such product as well as to secure high gas barrier property and transparency of the sealant film itself.
Furthermore, with regard to the transparent conductive substrate, for example, in the case of electronic paper, organic EL, liquid crystals or the like, it is commonly practiced that a transparent conductive layer on a film substrate is processed by lithography, etching or the like to form a wiring pattern, and then bonded to a counter-substrate, a rib or the like with an adhesive resin.
Therefore, when a transparent conductive film on which a wiring pattern formed from such transparent conductive layer or the like is formed, is bonded to another member (which constitutes an electronic or electric parts including a display element or the like) by means of an adhesive resin, it is desirable that the transparent conductive film and the adhesive resin are bonded uniformly and firmly, in order to prevent delamination of the transparent conductive film and the like due to environmental changes during product manufacturing processes after bonding or use of such product.
So far, it has been reported that the adhesiveness of the surface of an organic polymeric body is enhanced when the superficial groups of the organic polymeric body are modified through UV ozone treatment, corona discharge treatment or plasma treatment of the surface of the organic polymeric body for the purpose of improving the adhesiveness of the surface of the organic polymeric body and the adhesive resin. However, these modified superficial groups of the organic polymeric body infiltrate into the organic polymeric body under the effect of external environment, and as a result, there occurs a problem of deterioration of the adhesive strength to the adhesive resin over the standing time after the surface treatment of the organic polymeric body (See, for example, Non-patent Document 1).
In addition, patterning of the transparent conductive layer is frequently performed upon the formation of target elements, but there are cases where UV ozone treatment, corona discharge treatment, plasma treatment or the like cannot be carried out in some element forming processes.
By the way, compounds (including resins; hereinafter, the same) having isocyanate groups, carboxyl groups, or cyclic ether groups including epoxy groups are known to be useful for the bonding, that is, adhesion, coating, painting and the like, of various members (See, for example, Patent Document 3). These compounds have excellent bondability to various materials and are widely used in many fields such as adhesion, painting, coating and the like, based on this bondability. However, depending on the material of the counterpart, sufficient bondability is hardly expected. For example, in the case of adhering polyolefins, there were cases where sufficient adhesive strength could not be secured. In particular, there are many polyolefins, including cycloolefin (co)polymers and 4-methyl-1-pentene (co)polymers, that are difficult to be adhered, and there were cases where good adhesion could not be necessarily achieved even through the use of those compounds having the above-described functional groups.
Moreover, as described in Patent Document 1 and 2 described above, it is already known, with regard to films comprising organic polymers, to laminate layers comprising inorganic compounds including silicon oxide, silicon nitride or silicon oxynitride on the films comprising organic polymers.
For example, it is already known to form layers comprising inorganic compounds having nitrogen atoms, on the surfaces of various resins such as polyolefins. However, the main purpose of forming such layers is to enhance the gas barrier property, but investigation on the effect of the layers comprising nitrogen-atom-containing inorganic compounds on the adhesiveness of the resins has not been sufficiently achieved. Because of that, in conventional cases, bonding to an adhesive resin or the like has been carried out only after providing a coating layer comprising an inorganic oxide such as oxide of indium and tin, on the layer comprising a nitrogen-atom-containing inorganic compound such as silicon oxynitride (See, for example, Patent Document 4). This is because it is known that the adhesiveness to an adhesive resin is improved by forming a layer comprising an inorganic oxide on the surface of a molded product of organic polymer (See, for example, Patent Document 5).
However, although the adhesiveness to an adhesive resin is improved by forming a layer comprising an inorganic oxide film on the surface of the molded product of organic polymer, the adhesiveness was not necessarily sufficient in view of the purpose of the film. In particular, with regard to the uses in electronic and electric parts including display elements and the like, it is highly required to sufficiently seal the interior of the packages, cells and the like, and thus it is needed to materialize a sealant film having improved adhesiveness compared with the cases of using conventional inorganic oxide films.
In addition, it is already known to produce a transparent conductive film by laminating a layer comprising an inorganic compound such as silicon oxide, silicon nitride or silicon oxynitride on a film substrate comprising an inorganic polymer, and then forming a transparent conductive layer thereon. However, the main purpose of forming such layers is to enhance the gas barrier property and to improve the close adherence of the transparent conductive layer and the film substrate, and investigation on the adhesiveness of the layer comprising an inorganic compound and the adhesive resin (that is used for the bonding with other members) has not been sufficiently achieved (See, for example, Patent Document 6).
That is, there were cases where the adhesiveness between the transparent conductive film and the adhesive resin or the like as described above was not necessarily sufficient in view of the purpose of the film. Especially in the case where the organic polymer used for the film substrate was a polyolefin (in particular, cycloolefin (co)polymer), PET or the like, bonding of the transparent conductive film and the adhesive resin was not necessarily easy in many cases, and this caused limited use of transparent conductive films employing such substrates.
There is also known a substrate for transparent electrode in which one or more of each of nitride layers and oxide layers are laminated on a transparent substrate such as polyethersulfone, and then a transparent polymer layer such as silicone resin is laminated thereon. However, the main purpose of forming such layers is to improve the gas barrier property and the steam barrier property, and an investigation on the adhesiveness between these layers comprising inorganic compounds and the adhesive resin (that is used for bonding to other members) is not sufficiently achieved (See Patent Document 7).
Meanwhile, a laminate having an epoxy resin adhered on the surface of a body to be bonded via a silicon nitride film is known, and it is reported to enhance the adhesive strength under hygroscopic and high temperature conditions by forming a silicon nitride film on the surface of the body to be bonded and then adhering the resulting body to another member using an epoxy resin (See Patent Document 8). In this report, it is described that the body to be bonded may be a resin material, but in practice, the effect is merely confirmed in metallic materials, specifically iron and copper metals.
Patent Document 1; JP-A No. 2002-100469
Patent Document 2; JP-A No. 2004-330623
Patent Document 3; JP-A No. 11-279519
Patent Document 4; JP-A No. 2001-315276
Patent Document 5; JP-A No. 4-206760
Patent Document 6; JP-A No. 11-048388
Patent Document 7; JP-A No. 8-68990
Patent Document 8; JP-A No. 5-254053
Non-patent Document 1; “Chemistry of Surface Analysis-Modification”, The Adhesion Society of Japan, Nikkan Kogyo Shimbun, Ltd. (1st Edition published in 2003)